Many barrel-makers mark the twist rate and bore dimensions on their barrel blanks.
Does muzzle velocity change with faster or slower barrel twist rates? Absolutely, but much less than you might think. Faster twist rates do slow down bullets somewhat, but the speed loss is NOT that significant. With Bartlein .308 Win barrels of identical length and contour, a 1:12″-twist barrel was only 8 fps faster than a 1:8″-twist barrel. That was the result of testing by Applied Ballistics.
The Applied Ballistics team tested six (6) same-length/same-contour Bartlein barrels to observe how twist rate might affect muzzle velocity. This unique, multi-barrel test is featured in the book Modern Advancements in Long Range Shooting, Vol. 1. That book includes other fascinating field tests, including a comprehensive chronograph comparison.
Barrel Twist Rate vs. Velocity — What Tests Reveal by Bryan Litz
When considering barrel twist rates, it’s a common belief that faster twist rates will reduce muzzle velocity. The thinking is that the faster twist rate will resist forward motion of the bullet and slow it down. There are anecdotal accounts of this, such as when someone replaces a barrel of one brand/twist with a different brand and twist and observes a different muzzle velocity. But how do you know the twist rate is what affected muzzle velocity and not the barrel finish, or bore/groove dimensions? Did you use the same chronograph to measure velocity from both barrels? Do you really trust your chronograph?
Summary of Test Results
After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 FPS per inch of twist. In other words, your velocity is reduced by about 5 FPS if you go from a 1:12″ twist to a 1:8″ twist. — Bryan Litz
Savage Test Rifle with Six Bartlein Barrels
Most shooters don’t have access to the equipment required to fully explore questions like this. These are exactly the kinds of things we examine in the book Modern Advancements in Long Range Shooting, Vol. 1. In that book, we present experiments conducted in the Applied Ballistics lab. Some of those experiments took on a “Myth Buster” tone as we sought to confirm (or deny) popular pre-conceptions. For example, here’s how we approached the question of barrel twist and muzzle velocity.
Six .308 Win Barrels from Bartlein — All Shot from the Same Rifle
We acquired six (6) barrels from the same manufacturer (Bartlein), all the same length and contour, and all chambered with the same reamer (SAAMI spec .308 Winchester). All these barrels were fitted to the same Savage Precision Target action, and fired from the same stock, and bench set-up. Common ammo was fired from all six barrels having different twist rates and rifling configurations. In this way, we’re truly able to compare what effect the actual twist rate has on muzzle velocity with a reasonable degree of confidence.
Prior to live fire testing, we explored the theoretical basis of the project, doing the physics. In this case, an energy balance is presented which predicts how much velocity you should expect to lose for a bullet that’s got a little more rotational energy from the faster twist. In the case of the .30 caliber 175 grain bullets, the math predicts a loss of 1.25 fps per inch-unit of barrel twist (e.g. a 1:8″ twist is predicted to be 1.25 fps slower than a 1:9″ twist).
Above, data shows relationship between Twist Rate and Muzzle Velocity (MV) for various barrel twist rates and rifling types. From fast to slow, the three 1:10″ twist barrels are: 5R (canted land), 5 Groove, 5 Groove left-hand twist.
We proceeded with testing all 6 barrels, with twist rates from 1:8″ to 1:12″. After all the smoke cleared, we found that muzzle velocity correlates to twist rate at the average rate of approximately 1.33 fps per inch of twist. In other words, your velocity is reduced by about 5 fps if you go from a 1:12″ twist to a 1:8″ twist. [Editor: That’s an average for all the lengths tested. The actual variance between 1:12″ and 1:8″ here was 8 FPS.] In this case the math prediction was pretty close, and we have to remember that there’s always uncertainty in the live fire results. Uncertainty is always considered in terms of what conclusions the results can actually support with confidence.
This is just a brief synopsis of a single test case. The coverage of twist rates in Modern Advancements in Long-Range Shooting Vol. 1 is more detailed, with multiple live fire tests. Results are extrapolated for other calibers and bullet weights. Needless to say, the question of “how twist rate affects muzzle velocity” is fully answered.
Other chapters in the book’s twist rate section include: · Stability and Drag — Supersonic
· Stability and Drag — Transonic
· Spin Rate Decay
· Effect of Twist rate on Precision
Other sections of the book include: Modern Rifles, Scopes, and Bullets as well as Advancements in Predictive Modeling. This book is sold through the Applied Ballistics online store. Modern Advancements in Long Range Shooting is also available as an eBook in Amazon Kindle format.
Long Range Scope for Hunters — Quigley-Ford Dual Focal Plane
By James Mock
I recently tested a 5-20x50mm Quigley-Ford Dual Focal Plane Scope. This unique $3049.00 optic essentially offers DUAL focal reticles. The primary reticle is in the First Focal Plane while there is a SECOND reticle in the Second Focal plane. How is that possible? The scope is basically a First Focal Plane one, but there is an secondary Second Focal Plane reticle that does not change size (or thickness) when the magnification level changes. Quigley-Ford states: “The ONLY long range scope that is built with dual focal plane capability (without electronics or batteries) to make it effective for both long range shots AND close up.” The design holds U.S. Patent #D943050. This scope is assembled in Canada with German-crafted HD multi-coated lenses and a main tube from China.
The manufacturer explains: “The patented Dual Focal Plane scope provides a super bold Second Focal Plane etched aiming point … on all power settings PLUS a First Focal Plane reticle to provide the ability to shoot at any distance on any power. With this innovative combination a hunter in near darkness, using the lowest power setting can still pick up an aiming point on an animal with ease.” See how it works:
As seen in the photo, the two dark horizontal lines are in the second focal plane and are there to aid the “hunter” when the power is turned down and the fine cross hairs are difficult to see. This is an ingenious arrangement that allows one to use low power settings in dim light without losing sight of the reticle. NOTE: When ordering one of these scopes, one must give Randy Ford the particulars of the load to be shot. The required data includes caliber, bullet weight, bullet BC, and velocity. My load data sent to Randy was: 32.2 grains Varget, CCI 400 SR primer, 108gr Berger BT at 2910 FPS.
Randy emphasized that there are other factors to consider such as altitude, but his reticle is seldom off on distant targets more than 2 inches. He repeated that his system is designed for the hunter to quickly find an aiming point. They recommend a default altitude of 5000 feet. That way the reticle will still be very effective from sea level to 10,000 ft.
To set up the FFP system, one zeroes the rifle at 200 yards. The center crosshair will be for 200 yards with hash marks to 1000 yards with smaller marks between the longer 100-yard marks.
In the photos below, I first shot over the chronograph to check my velocity. It is very important to match the velocity for which the reticle was designed. The velocity was within a few FPS of the velocity I provided to Randy. His system utilizes marks for hold-over rather than having to dial the scope. It is a very ingenious system. Although I am 79 years old, I still enjoy shooting. I wish I could have had a scope like this one when shooting at a mule deer in Colorado back in 1980. After checking velocity, one must obtain a 200-yard zero. I did this at my friend Kent Bennett’s 200-yard range…on which I have shot for many years. My rifle is a Stolle Panda with 28″, 1:7.5″-twist Krieger barrel chambered in 6mm Dasher.
Speaking of Kent, he was impressed with his initial contact with this scope. He stated that the optics were very sharp and clear. I will add that the adjustments were spot on and the parallax was easily removed. My next trip to the range was to another friend’s 600-yard range.
Parallax Adjustment: Side-focus
Click Adjustments: 1/4″ @ 100 yards
Length: 15.75″ plus sunshade
Weight: 25.5 ounces
Finish: Matte black
With the preparations completed, I took my Dasher with the Quigley-Ford scope to a friend’s range. He had targets set up at 200, 300, 400, and 600 yards. The morning was foggy with light drizzle, but the rain held off until I finished the test.
I started by checking my 200-yard zero and it was close, although not perfect. Next, I shot 300 yards, 400 yards, and at a 600-yard steel gong. The 300-yard shot (shown at right) was perfect except for being a tad right. I was very satisfied with the results so far. I skipped 500 yards temporarily, but went to the gong at 600 yards. There was a very satisfying “bong!” when the 108gr bullet arrived. This showed that the scope can provide precise elevations for distances from 200 to 600 yards.
I then set up a plywood dummy deer (crafted by my son years ago) at 500 yards and shot it twice. One shot was with the 108gr Berger BT and the other was with a 105gr, Bart’s VLD. Both were about 2910 FPS and have a BC that is very close. When I went to the target, I was pleasantly surprised in that the bullets were close to center and less than 1 inch apart. Both were 10s and one was an “X”.
Conclusion: I will continue more testing of this Dual Focal Plane scope. So far, I find that it is a very worthwhile addition to a long-range hunter’s rifle. I was amazed at how precise the reticle was from 200 to 600 yards. The Dual Focal Plane functionality is unique and very useful — offering the “best of both worlds” for hunting — you have a highly visible horizontal bar, combined with a FFP reticle which allows precise holds at multiple ranges. Stay tuned, James Mock.
AccurateShooter.com is more about rifles than pistols. But we know that the majority of our regular readers own handguns, and many also have concealed carry (CCW) permits. And with the prospect of social unrest following the election, we expect more reader than ever will be “packing” a sidearm. Accordingly, we’ve found a great resource for CCW holders that can help you select a holster. On the Shooting Illustrated website you’ll find a detailed review of 30 different holster types. Each holster is illustrated, with pros and cons explained. These are all EDC holsters, meaning those designed for “Every Day Carry”.
Shooting Illustrated calls this article “HolsterPallooza” and it really does provide a ton of helpful information. Most other holster reviews on the web may feature a half-dozen holsters at the most. In this Holsterpallooza article you can see 30 holsters, with a wide variety of materials, designs, and applications. There are small molded IWB holsters for CCW, conventional on the belt holsters, leather shoulder holster rigs, and even ankle holsters. This is a great place to start if you are in the market for a holster.
Here’s sample of the many holster options reviewed, an innovative hybrid IWB holster constructed with leather over Kydex. That gives you the “best of both worlds” — the secure fit/retention of a molded Kydex shell, with an attractive leather exterior.
Shooting Illustrated explains: “As the interface between your gun and your body, the holster is a vital component of your carry rig. In many cases, the circumstances of your daily life will determine the method of carry you choose. This, in turn, will determine what type of holster you need, which may end up determining the handgun you carry. Therefore, choosing the method and type of holster may be as, or even more important than, choosing a firearm.”
MORE Reviews — Hickok 45 Reviews 15 CCW Holsters:
If you want to see even MORE holsters for “Every Day Carry” (EDC), check out this video from Hickok 45. This popular YouTube host looks at 15 different IWB holsters from a number of manufacturers. Hickok 45 examines many hybrid holsters that combine Kydex or plastic with leather for increased comfort. He has his favorites… and they might not be what you’d expect. NOTE: As this video has been watched over 900,000 times, you may also want to read the viewer comments. There are many helpful suggestions from CCW holders who carry daily.
While some shooting disciplines have moved to electronic targets, most shooting matches still use paper targets, which must have precise dimensions for the particular distance and discipline. If you need correctly-sized targets for specific shooting disciplines (such as NRA Smallbore, F-Class, and 1K Benchrest) check out the links in this article. Precise, dimensionally-correct competition targets are produced by a half-dozen specialty printers. In this article we provide links to the leading target sellers, with a chart showing “who’s got what”. Look for your particular discipline and the vendors will be specified.
Sources for Official Shooting Competition Targets:
AccurateShooter.com offers dozens of FREE, printable targets for target practice, load development, and fun shooting. We also offer a few of the most popular NRA Bullseye targets. One or more of these printable targets should work for most training purposes. However, some readers have asked: “Where can we get the real targets… exactly like the ones used in NRA, IBS, and NBRSA shooting matches?”
All these vendors carry nearly all the NRA High Power and Smallbore targets, including the smaller F-Class targets. National Target has the F-Class and High Power targets, including 100-yard reductions of the 200, 300, and 600-yard military targets.
Here are some of the air rifle, smallbore, and High Power targets at Creedmoor Sports:
Orrville Printing currently sells IBS targets for rimfire (50 yard) benchrest, short-range centerfire Benchrest (100, 200, 300 yards), Hunter BR Rifle (100, 200, 300 yards), plus the official 600-yard and 1000-yard IBS targets. National Target Company also has most of the IBS targets. NBRSA short-range, 600-yard, and 1000-yard benchrest targets are available directly from the NBRSA Business Office. Send an email to nbrsa@icloud.com or call (434) 993-9201.
Good Source for Specialty Targets and Target Stands
Need Steel, Cardboard Silhouettes or specialty targets? ALCO Target Company in Duarte, California is the USA’s leading producer of the full spectrum of shooting targets including paper targets, cardboard targets, steel targets, and target stands.
“A bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, the bullet behaves as if it has a higher ballistic coefficient.”
A few seasons back a good friend ventured to the high country of Colorado to pursue elk. He recently zeroed his rifle in California, at a range just a few hundred feet Above Mean Sea Level (AMSL). He wondered if the higher altitude in Colorado could alter his ballistics. The answer is a definite yes. However the good news is that free ballistics calculators can help you plot reliable drop charts for various shooting locations, high or low.
The question has been posed: “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, at higher altitudes, the bullet behaves as if it has a higher ballistic coefficient.
Forum member Milanuk explains that the key factor is not altitude, but rather air pressure. Milanuk writes:
“In basic terms, as your altitude increases, the density of the air the bullet must travel through decreases, thereby reducing the drag on the bullet. Generally, the higher the altitude, the less the bullet will drop. For example, I shoot at a couple ranges here in the Pacific Northwest. Both are at 1000′ AMSL (Above Mean Sea Level) or less. I’ll need about 29-30 MOA to get from 100 yards to 1000 yards with a Berger 155gr VLD at 2960 fps. By contrast, in Raton, NM, located at 6600′ AMSL, I’ll only need about 24-25 MOA to do the same. That’s a significant difference.
Note that it is the barometric pressure that really matters, not simply the nominal altitude. The barometric pressure will indicate the reduced pressure from a higher altitude, but it will also show you the pressure changes as a front moves in, etc. which can play havoc w/ your calculated come-ups. Most altimeters are simply barometers that read in feet instead of inches of mercury.”
As Milanuk states, it is NOT altitude per se, but the LOCAL barometric pressure (sometimes called “station pressure”) that is key. The two atmospheric conditions that most effect bullet flight are air temperature, and barometric pressure. Normally, humidity has a negligible effect. It’s important to remember that the barometric pressure reported on the radio (or internet) may be stated as a sea level equivalency. So in Denver (at 6,000 feet AMSL), if the local pressure is 24″, the radio will report the barometric pressure to be 30″. If you do high altitude shooting at long range, bring along a Kestrel, or remember to mentally correct the radio station’s pressure, by 1″ per 1,000 feet.
Trajectory of Bullet fired at Sea Level
Trajectory of Bullet fired at 20,000 feet
You can do your own experimental calculations using JBM Online Ballistics (free to use). Here is an extreme example, with two printouts (generated with Point Blank software), one showing bullet trajectory at sea level (0′ altitude) and one at 20,000 feet. For demonstration sake, we assigned a low 0.2 BC to the bullet, with a velocity of 3000 fps.
To learn more about all aspects of Exterior Ballistics, Hornady has a useful discussion of External Ballistics including the effects of altitude and temperature. To dig deeper, Sierra Bullets has a comprehensive Exterior Ballistics Resource Page with multiple sections from the Sierra Manual (4th and 5th Editions), including:
Example from Section 3.0: “When a bullet flies through the air, two types of forces act on the bullet to determine its path (trajectory) through the air. The first is gravitational force; the other is aerodynamics. Several kinds of aerodynamic forces act on a bullet: drag, lift, side forces, Magnus force, spin damping force, pitch damping force, and Magnus cross force. The most important of these aerodynamic forces is drag. All the others are very small in comparison when the bullet is spin-stabilized.”
Gunsmith/stockmaker Doan Trevor created a lovely, one-of-a-kind silhouette stock for an Anschutz rimfire action. Built as a true custom design, this stock combines ideal standing position ergonomics with light weight — the entire stock weighs a mere two pounds. This project really showcases Doan’s remarkable skills with wood. Read the full story about this project (with more photos) at DoanTrever.com.
Doan explains his design process: “A customer came to me wanting to know if I could build a silhouette stock that was 2 pounds or less. I used the Koa wood because it is a lower specific gravity than Walnut (which makes it lighter) and stronger. I was still able to use pillar bedding and keep the weight down. The fore-end could be shortened to reduce the weight even more.
Since the drops on a silhouette rifle are different than a prone rifle, I kept the pistol grip from the prone rifle which is comfortable and tried to come up with a higher cheek piece and more drop to the buttplate. All of this required lots of hand carving.”
The USA F-Class National Championships are underway right now in Lodi, Wisconsin. The Mid-Range Championships run August 10-13, 2024, while the Long Range F-Class Championships start on the 14th and run through August 17, 2024. With the Mid-Range event underway today, as you read this, top F-Open and F-TR shooters are aiming their rifles at 600-yard targets. VIEW Nationals Match Program HERE.
2024 NRA F-CLASS NATIONAL CHAMPIONSHIPS
NRA F-CLASS MID-RANGE NATIONAL CHAMPIONSHIP AUGUST 10-13, 2024
NRA F-CLASS LONG RANGE NATIONAL CHAMPIONSHIP AUGUST 14-17, 2024
Event hosted by Winnequah Gun Club and sponsored by Brux Barrels, Criterion Barrels, Krieger Barrels, and Silver Mountain Target.
There will be two divisions at The F-Class National Championships: F-Open and F-TR. In F-Open the rifles can shoot any cartridge type (up to .35 caliber) and have a 22-lb (10kg) weight limit. A front rest is allowed, and most shooters favor a rest with a joystick control.
In F-TR, two cartridge types are allowed: .223 Remington (5.56×45) or .308 Winchester (7.62×51 NATO), with no restrictions on bullet weight. F-TR rifles are fired off a bipod attached to the rifle’s fore-end. The F-TR weight limit is 8.25 kilograms, or about 18 pounds. This includes the weight of the rifle, scope, and bipod. A sandbag can be used under the rear of the stock. Because of the lower weight limit, which includes the bipod, F-TR stocks tend to be much slimmer and lighter than F-Open stocks which have wide fore-arms to work with the front rests.
F-Open Cartridge Options — Modern Magnum Options
For Today’s Sunday Gunday Story we feature an article about F-Open chamberings by respected rifle builder and past F-Open National Champion Emil Kovan. In this article, Emil reviews some of the new magnum cartridge options that are being employed by F-Open competitors. Many shooters are still using the .284 Winchester (or variants), but an increasing number are shooting 7mm and .30-caliber cartridges based on magnum cartridge types. The 7mm is probably still the favored caliber for F-Open because 7mm bullets offer great ballistics with less recoil than heavier .30-caliber projectiles.
Cartridges for F-Class Part II — Rise of the Magnums
A few seasons back, I wrote an article on cartridge choices for F-Class shooters. CLICK HERE to READ ARTICLE. Since the first article I wrote, F-Class has continued to grow, and push the limits of precision and accuracy. While the .284 Win and its variants are still the most common F-Open cartridges, more and more top F-Open shooters are using magnum cartridge types to win competitions and set new records. In this article, I will list some of the advantages and disadvantages of the most commonly used magnums, and will cover the strengths and weaknesses of each one of them.
Performance factors we will consider for magnum F-Open cartridges include:
1. Equal or better accuracy than standard chambers
2. Better ballistic performance
3. Enhanced case life
4. Barrel life
Accuracy Potential of Magnum Cartridges for F-0pen Competition
John Meyrs has won four National Mid-Range Championships using the .300 WSM. Tim Vought used the same cartridge to win two Mid-Range Nationals and used a 7-6.5 PRC to win the long range Nationals. Standard .437″ case head (.308 Win head size) cartridges still have more Nationals wins overall, but the magnums are quickly catching up, and my prediction is that magnums will dominate soon.
The accuracy and precision potential of magnums used in F-Class (.300 WSM, 7-270 WSM, 7mm RSAUM or “7 SAUM”, 7-6.5 PRC) is better than non-magnum cartridges because their shapes are closer to the ideal “fat/short” body associated with wider nodes and extreme precision. For example a .300 WSM is proportionally much closer to the 6 PPC, 6 Dasher, and 6 BRA than is the .284 Winchester.
Stunning F-Open rifle with SEB Mini front rest with Blake Machine accessories.
The first thing that comes to mind when magnums are discussed is power and speed. In my humble opinion most shooters are missing out on accuracy because they push their magnums right past the most stable and accurate nodes. Recently I met my good friend from the Army Marksmanship Unit, SFC Brandon Green, at a shooting competition. We discussed the latest and greatest in long-range shooting. I knew that the USAMU had switched from 6.5-284 Norma to 7mm RSAUM several years back, but didn’t know what load they are currently using. Brandon told me that the load featured Berger 180gr hybrids in Nosler cases at 2820 fps. We all know that the 7 SAUM is capable of much higher speeds, “but at around 2820 fps the load/rifle combo will hammer the X-Ring anywhere under any conditions” SFC Green said.
F-Open rifles on the firing line at the Ben Avery Shooting Facility in Phoenix, Arizona.
Most shooters jump right into magnum territory velocities when testing, missing out on better precision at standard chamber speeds. For example, my 30 KMR can easily reach 2880 fps with 230gr Hybrids, and it actually shoots pretty good. But the same rifle at around 2770 fps will absolutely hammer the X-Ring in any condition anywhere. When it’s all said and done, F-Class is a long-range shooting competition at a known distance which requires extreme precision and accuracy. It is not a speed race.
IMPORTANT — Case-Head Dimensions Do Make a Difference
Magnums, when shot within reasonable velocities, on average will give better case life due to the bigger case + lower pressure and “more meat” in the case-head area. For example a 7 SAUM case will outlast a .284 Win case when both are loaded to around 2900 fps.
Disadvantages of Magnum F-Open Cartridges
Perhaps the biggest disadvantage linked to magnums is recoil. Some people complain about developing the “gun shy” syndrome after shooting a magnum for a while. Muzzle blast and recoil are significantly more pronounced in magnums, but that can be easily managed with a properly-built rifle equipped with appropriate recoil mitigation hardware such as RAD and the various butt plates.
F-Open rifle equipped with recoil reduction buttpad system.
Barrel Life — “Barrels are Expendable Components”
It is true that certain magnums can torch a barrel in just a few hundred rounds. But the same is true when improving a 6BR to 6 Dasher for example — barrel life might be reduced significantly. More powder = more heat = diminished accuracy after a certain round count. In my experience, a F-Open magnum’s barrel life is very close to high-performance standard cartridges such as the .284 Shehane or .284 KMR. I “retire” my barrels around 1200 rounds regardless of the cartridge being a magnum or not. After that many rounds most barrels will still shoot OK but will copper up, and you will start seeing those unexplained vertical 9s. The bottom line is this, barrels are expendable components very much like brass. You can’t get the performance of .300 WSM and the barrel life of the .308 Win at the same time. If you want to race in NASCAR, fuel mileage should not be the top priority!
Top Magnum Cartridge Types Used in F-Class Open Division
.300 Winchester Short Magnum
The .300 WSM (Winchester Short Magnum) tops the popularity chart in F-Class Open division. It has been used to win numerous National championships and has set many National records. The .300 WSM’s short/fat case shape, with minimal body taper and 35-degree shoulder, contribute greatly to its outstanding performance at long range. Components are readily available as well. Best brass remains to be Norma, although ADG is just as good and some would even say better, but it is more expensive and harder to get at this time.
The .300 WSM has been described as a “super-sized Dasher”.
For the .30-cal magnums, in my opinion, the best bullets by far are made by Berger. If your rifle does not shoot 215gr, 230gr hybrids, or 210gr VLDs well, you likely have a rifle problem, NOT a bullet issue. My “go to” bullet is the Berger 230gr Hybrid. The 215-grainer is a close second, followed by Berger’s accurate but ballistically inferior 210gr VLD, which I use in calm and steady conditions.
Top powders for the .300 WSM are Hodgdon H4831SC and H4350. I know there are many more powders suitable for the .300 WSM cartridge, but none I have used can match Hodgdon’s consistency when shot in different geographical locations and weather conditions.
7mm Remington Short Action Ultra Magnum
The 7mm RSAUM (aka 7 SAUM) used to be the darling of F-Open. Its case capacity and shape are about perfect for launching 180gr pills with great ballistics and precision. Its popularity faded a little, due to the lack of good brass, and the rise of the improved versions of the .284 Win which can almost match the RSAUM performance. Norma still makes 7 RSAUM brass which is pretty good but little on the soft side and hard to find. ADG is arguably producing the best RSAUM brass right now. It is very uniform, reasonably priced, and seems to hold up very well even when pushed hard. The best bullets are again made by Berger, and those are the 180gr hybrid, 184gr hybrid, and 180gr VLD. Best powders are H4831sc, H4350, and Alliant Reloder 16 and Reloder 23.
7-270 WSM, 7-300 WSM, and 7 WSM
The first two are pretty much identical, the only difference being that the 7-270 WSM is necked up .270 WSM while the 7-300 WSM is a .300 WSM necked down to 7mm. I personally prefer the first one since necking-up is easier than necking-down (with fewer doughnut issues).
The WSM case-based 7mms will give you great velocity flexibility as well as superb precision when tuned well. In the 2013 world championship in Raton NM, I was scoring for a gentleman from Canada who was shooting 7-270 WSM. The wind was blowing pretty hard that day. On one of his shots, just before he pulled the trigger the wind gusted. I remember thinking that’s going to be an 8 for sure. The target came up a line 10! I asked him after the match what he was shooting, and he replied 180s at 3100fps. Although capable of such speeds, I think that potentially better and more consistent accuracy can be achieved at much slower speeds. The best powders and bullets are again Hodgdon and Berger respectively. Best cases are made by Norma and ADG, with Winchester being a third option.
7-6.5 PRC — Popular Wildcat
Last but not least on our chart is the 7-6.5 PRC. This particular cartridge is actually a wildcat. It is a 6.5 PRC necked up to 7mm. It is pretty much identical to the 7 RSAUM with the only differences being a shorter neck and .01″-narrower body. Currently the 7-6.5 PRC is the most requested cartridge that I offer when building new rifles. It seems to fill the gap between the .284 Win and the larger magnums very nicely. It is capable of reaching 3000fps but most shooters are getting their best results around 2920-2950 fps. The biggest advantage of this wildcat is brass. Lapua makes super high-quality, readily-available 6.5 PRC brass. Best powders are H4831sc, H4350, Reloder 16, and Vihtavuori VV 555. The best bullet in my opinion is the 180gr Berger. I am yet to hear about a better-performing bullet in this chamber.
Conclusion In conclusion, magnums are not perfect but their performance advantages should be very seriously considered when building a rifle for long-range F-Class. In part three, I will list the most common wildcat magnums, and present the KMR magnums which will make you (if you haven’t already) buy a magnum action and get a magnum build for sure!
– 2014 F-Class Open National Champion
– 2015 F-Class Open National Championship, Silver Medal
– F-Class Open National Championship Teams, 2015, 2014, 2013, Shooting Team Member
– Over 15 wins in Regional and State Championships in Palma, F-TR, F-Open
– 2013 U.S. National Team Member
– 2023 F-Open Gold Medal Team USA Member, 2023 World Championship in South Africa
Sam (L.E.) Wilson actively competed in benchrest matches until he passed. He’s shown here with an Unlimited benchrest rifle of his own design.
If you’ve used hand dies with an arbor press, chances are you’ve seen the L.E. Wilson company name. You may not know that the founder of L.E. Wilson Inc. was an avid benchrest competitor who pioneered many of the precision reloading methods we used today. Known as “Sam” to his friends, L.E. Wilson was one of the great accuracy pioneers who collected many trophies for match victories during his long shooting career. His company continues to innovate — bringing out new products such as the Case Gage Depth Micrometer tool.
The photo above shows Sam (foreground) with all of his children at a shoot. Behind Sam are Jim, Jack and Mary, shooting in the Unlimited Class. What do they say — “the family that plays together stays together”? Note the long, externally-adjusted scopes being used. Learn more about Sam (L.E.) Wilson and his company on the L.E. Wilson website.
Unlimited Class was Sam’s favorite discipline, because in the “good old days” top competitors normally would craft both the rifle and the front/rear rests. This rewarded Sam’s ingenuity and machining/fabrication skills. In the “build-it-yourself” era, one couldn’t just order up an unlimited rail gun on the internet. How times have changed…
It’s summertime, so many folks will head to the hinterlands on prairie dog safaris. On a good P-Dog adventure, you may shoot hundreds of rounds over a long weekend. So you’ll need plenty of ammo. With these ammo volume requirements, you probably won’t have time to load to benchrest standards, and you may not have the budget for match-grade bullets. To save time you may throw (rather than weigh) your charges, or even load on a progressive press. This all raises the question of ammo accuracy — how good is “good enough”? A Sierra Bullets expert answers that question here — explaining how to efficiently load ammo for varmint work.
Ammunition Accuracy Requirements 101 — Varmint Ammo
This story based on article by Sierra Bullets Chief Ballistician Tommy Todd
I load and shoot ammunition for a living. In my duties here at Sierra I constantly test bullet accuracy for our production needs. Because of this, I shoot a variety of different calibers and cartridges on a daily basis and a large demand of this shooting is keeping the guns and loads tuned for optimum accuracy. I have a very narrow window of tolerances to maintain in order to provide our customers (you) with the most accurate bullets on the market.
I have learned many tricks and techniques over the years to tuning a load, prepping brass, and cleaning barrels to keep a gun shooting. I often utilize the things I have learned and take them to extreme levels when competing in a shooting event. I also often ignore most of these things (other than safety) and simplify the process if the shooting I will be doing does not warrant.
[One summer] I went on a prairie dog shoot in Wyoming with some good friends. The targets cooperated as did the weather with the exception of some challenging winds we experienced. We had a great time and make a lot of hits on those small rodents. When loading for the .223 Remington rifles and the TC Contender, I cut a few corners in the ammunition-loading process due to both time constraints and accuracy needed. When shooting at a prairie dog a miss is simply that, but when shooting at say the X-Ring at 1000-yard competition, a poorly-placed shot [harms your] placing in the match. Because of this, I can afford to miss an occasional shot at a varmint due to ammunition capability without worry but will not allow the same tolerances in my match ammo. For the Wyoming trip I utilized a powder measure and simply dumped the charges into primed cases that had been full-length sized and primed.
I had measured enough for length to know that while there was some variance all were under maximum length. I know there is some variation of the measure I utilized but not significant enough to warrant weighing every charge. When seating the bullets a competition seating die was used and I verified OAL on the occasional cartridge to make sure nothing changed.
This varmint ammo, with thrown charges, put TEN shots inside ONE inch at 200 yards. That’s half MOA. Good Enough? Absolutely!
The ammo produced shot under one inch at 200 yards in one of the guns I planned on taking on to Wyoming with me. [Editor: That was for TEN Shots — see above.] I knew I had loaded ammunition that was quite suitable for the task at hand which was evidenced by the number of hits I was able to make at fairly long range.
NOTE: The author, Tommy Todd, explains that, when loading ammo for F-Class matches, he uses more exacting methods. He weighs every charge and seats his bullets carefully with an arbor press. Todd adapts his methodology for his particular application. The lesson here is to load to the level of precision demanded by your discipline. READ Full Story HERE.
A while back, Sinclair International’s Reloading Press Blog featured a “round-table” discussion of reloading techniques. Sinclair’s team of tech staffers were asked: “What do you feel is the one-most crucial step in precision reloading?”
Here are their responses (along with comments from our Editors):
Phil Hoham: “I feel that when working up a load do not go too high or too low in your powder charge. Stay away from ‘suggested loads’ you hear at the range, or on the internet. Always be sure to use a published reloading manual that presents not only minimums and maximums, but also pressure, velocity, and a proper range of powders used. Do not get distracted in the reloading process, and remain focused at all times during each step involved.”
AccurateShooter.com: Some loads presented on the Internet are OK as a starting point, but it is absolutely critical to understand that pressure maximums will vary considerably from one rifle to another (of the same chambering). For example, one 6mmBR rifle shooting 105gr bullets can max out with 30.0 grains of Varget powder, while another rifle, with the same chamber dimensions, but a different barrel, could tolerate (and perform better) with half a grain more powder. You need to adjust recommended loads to your particular rifle and barrel.
Pete Petros: “This could be a very broad topic, but if I were to pick one, it would be making sure to pay close attention, and weigh each and every powder charge to ensure that each load is exact and consistent. This is important not only for accuracy, but also for safety reasons.”
AccurateShooter.com: If you’re shooting beyond 200 yards, it is critical to weigh your loads with an accurate scale or automated system such as the AutoTrickler V3/V4. Loads that are uniform (within a few kernels) will exhibit lower Extreme Spread and Standard Deviation. And remember, even if you stick with the same powder, when you get a new powder lot, you may have to adjust your load quite a bit. For example, .308 Palma shooters have learned they may need to adjust Varget loads by up to a full grain from one lot of Varget to the next.
Ron Dague: “I feel that the most important step(s) in reloading for accuracy are in the initial case prep. Uniforming the primer pocket to the same depth to ensure consistency in primer seating is a crucial step. Additionally de-burring the flash holes, each in the same way to clean up and chamfer the inside is important. It ensures that the ignition from the primer is uniform and flows out in the same consistent pattern. Doing so will create uniform powder ignition and tighten up your velocity Extreme Spread.”
AccurateShooter.com: With some brands of brass, primer pocket uniforming and flash-hole deburring is useful. However, with the best Lapua, Norma, and RWS brass it may be unnecessary, or worse, counter-productive. So long as your Lapua brass flash-holes are not obstructed or smaller than spec, it may be best to leave them alone. This is particularly true with the small flash holes in 220 Russian, 6BR, and 6.5×47 cases. MOST of the flash-hole reaming tools on the market have cutting bits that vary in size because of manufacturing tolerances. We’ve found tools with an advertised diameter of .0625″ (1/16″) that actually cut an 0.068″ hole. In addition, we are wary of flash-hole deburring tools that cut an aggressive inside chamfer on the flash-holes. The reason is that it is very difficult to control the amount of chamfer precisely, even with tools that have a depth stop.
Rod Green: “I feel that bullet seating is the most important step. If you had focused on making sure all prior steps (case prep, powder charge, etc.) of the process have been carefully taken to ensure uniformity, bullet seating is the last step, and can mean all the difference in the world in terms of consistency. Making sure that the bullet is seated to the same depth each time, and time is taken to ensure that true aligned seating can make the load.”
Bob Blaine: “I agree with Rod. I strongly feel that consistent bullet seating depth is the most important step in creating the most accurate hand loads. I have seen the results in both my bench and long range rifles. Taking the time to ensure exactness in the seating process is by far, the number one most important step in my book.”
AccurateShooter.com: Agreed. When loading match ammo, after bullet seating, we check every loaded round for base of case to ogive length. If it varies by more than 3 thousandths, that round is segregated or we attempt to re-seat the bullet. We measure base of case to bullet ogive with a comparator mounted on one jaw of our calipers. You may have to pre-sort your bullets to hold the case-base to ogive measurement (of loaded rounds) within .003″.
This is just a brief synopsis of a single test case. The coverage of twist rates in Modern Advancements in Long-Range Shooting Vol. 1 is more detailed, with multiple live fire tests. Results are extrapolated for other calibers and bullet weights. Needless to say, the question of “how twist rate affects muzzle velocity” is fully answered.
With the preparations completed, I took my Dasher with the Quigley-Ford scope to a friend’s range. He had targets set up at 200, 300, 400, and 600 yards. The morning was foggy with light drizzle, but the rain held off until I finished the test.
The question has been posed: “What effect does altitude have on the flight of a bullet?” The simplistic answer is that, at higher altitudes, the air is thinner (lower density), so there is less drag on the bullet. This means that the amount of bullet drop is less at any given flight distance from the muzzle. Since the force of gravity is essentially constant on the earth’s surface (for practical purposes), the bullet’s downward acceleration doesn’t change, but a bullet launched at a higher altitude is able to fly slightly farther (in the thinner air) for every increment of downward movement. Effectively, at higher altitudes, the bullet behaves as if it has a higher ballistic coefficient.
There will be two divisions at The F-Class National Championships: F-Open and F-TR. In F-Open the rifles can shoot any cartridge type (up to .35 caliber) and have a 22-lb (10kg) weight limit. A front rest is allowed, and most shooters favor a rest with a joystick control.
In conclusion, magnums are not perfect but their performance advantages should be very seriously considered when building a rifle for long-range F-Class. In part three, I will list the most common wildcat magnums, and present the KMR magnums which will make you (if you haven’t already) buy a magnum action and get a magnum build for sure!
A while back, Sinclair International’s Reloading Press Blog featured a “round-table” discussion of reloading techniques. Sinclair’s team of tech staffers were asked: “What do you feel is the one-most crucial step in precision reloading?”
